The invention relates generally to ramps and more particularly to cargo ramps used to provide aircraft with multi role functions such as in flight refueling and cargo transport.
Modern aircraft which have the capability of transfering fuel to another aircraft while in flight generally use permanently installed fuel tank systems and fuel transfer systems. These "tanker" aircraft employ either of two fuel transfer systems, the probe and drogue system or the boom system. The probe and drogue system employs a flexible hose with a receiver drogue at the end which trails behind the tanker aircraft. The receiver aircraft employs a probe which engages a fitting in the drogue. When engagement is made, fuel is pumped to the receiver aircraft. The system is retracted by rolling the hose up on a large reel in the tanker aircraft. The boom system employs a rigid, telescoping boom which is hinged at the tanker aircraft's aft end. The boom location is controlled by aerodynamic surfaces to mounted to it. A fitting at the end of the boom engages a receptacle in the receiver aircraft, and fuel is transferred. The system is retracted by telescoping the boom to minimum length and hoisting the boom up against the aft underside of the aircraft. Although some tanker aircraft are converted cargo aircraft which may be reconverted back to a cargo aircraft configuration, the conversion process is very time consuming and in practice is not actually done. In addition, although some tanker aircraft are capable of carrying both cargo and fuel simultaneously, or only fuel, or only cargo, such aircraft are not able to operate from short or austere fields. Furthermore, these aircraft require extensive material handling equipment to function as cargo aircraft, and they cannot handle large rolling stock loads such as trucks and tracked vehicles. Other cargo aircraft which have been converted to tanker aircraft are capable of probe and drogue refueling operations but not boom refueling operations.
In different phases of a military operation there may be variations in demand for tanker and cargo aircraft. Sometimes demand for cargo aircraft is high while demand for tanker aircraft is low, and vice versa. The time period of these fluctuations may be quite short. Consequently, there may be difficulty in meeting such demands within the time period required with the result that the military operation may be handicapped.
Some prior art aircraft incorporate different and interchangeable sections into the basic airframe structure in order to allow the aircraft to accomodate many different types and sizes of payloads so that the aircraft can best fulfill a number of different mission objectives. An example of such a prior art aircraft is disclosed in U.S. Pat. No. 4,449,679 to McComas. However, the McComas invention can only be applied to twin-tailboom type aircraft. In addition, the demountable portion of the aircraft cannot function as a cargo ramp and cannot be rotated in pitch or roll to accomodate loading platforms, loading trucks, etc.
Other prior art aircraft incorporate removable cargo floors so that the floor can function as a preloaded cargo pallet in order to reduce loading and unloading time. An example of such a prior art aircraft is disclosed in U.S. Pat. No. 2,876,969 to Tydon. The Tydon disclosure describes a rapidly removable aircraft floor which can tilt and function as a ramp. However, The Tydon floor is a major fraction of the aircraft fuselage structure requiring substantial structural compromises to the airframe. In addition, since the Tydon floor lacks independent pitch, roll and vertical motion capability, it lacks the ability to align with other cargo vehicles.
A ramp system is thus needed that is capable of providing ramp alignment with cargo vehicles. Additionally, a ramp system is thus also needed that is capable of providing very rapid conversion between an aircraft providing a specialized operational function such as, for example, a full-fledged tanker aircraft (with both probe-and-drogue and boom capability) and a full-fledged cargo aircraft. A system is also needed that can provide such conversion while being simple and easy to use.